Israeli Defense Minister Israel Katz said on Monday that Hezbollah chief Naim Qassem was now a "target for elimination", after the Iran-aligned militant group fired at Israel in retaliation for the killing of Iran's Supreme Leader Ali Khamenei.
On Sunday, Qassem said in a statement: “We will undertake our duty of confronting the aggression," adding that his movement would not leave "the field of honor and resistance".
Israeli strikes on Lebanon killed at least 31 people on Monday, authorities said, following rocket fire from Tehran-backed militant group Hezbollah after the killing of Khamenei.
Israel's military vowed to intensify its attacks on the country and make Hezbollah pay a "heavy price" after launching several strikes on Beirut's southern suburbs and south Lebanon, areas where Hezbollah holds sway.
Lebanese authorities, who have been trying to spare the country from any repercussions of the US-Israeli attack on Iran, said Hezbollah's rocket fire gave Israel "excuses" to ramp up its attacks.
Lebanese President Joseph Aoun said attacks from the country's territory risked drawing the country into regional conflict.
Lebanese Prime Minister Nawaf Salam, whose government has pushed for Hezbollah's disarmament, called Monday's rocket fire "irresponsible".
He vowed to "stop the perpetrators and protect the Lebanese people".